fast-uri vulnerable to server-side request forgery via repeated hostname percent-decoding
漏洞描述
### Impact `fast-uri` decodes a hostname's percent escapes twice in a single `normalize()` or `resolve()` call: once during parsing and again during authority recomposition. A nested percent-encoded host therefore survives the first decode and is turned into a live destination by the second, so `normalize('http://%256c%256f%2563%2561%256c%2568%256f%2573%2574/')` returns `http://localhost/`. Applications that normalize or resolve an untrusted URI before an SSRF check, redirect validation, or host allowlist can be steered to a different destination, including internal addresses such as loopback or a cloud metadata endpoint, than the encoded input appeared to contain. This is an incomplete-fix variant of CVE-2026-6322, whose encoded-authority-delimiter fix introduced the second decode. ### Patches Fixed in `fast-uri` 2.4.5, 3.1.6, and 4.1.3. ### Workarounds Reject untrusted URIs whose host component contains an encoded percent sign (`%25`) before passing them to `normalize()` or `resolve()`. Source Code Location: https://github.com/fastify/fast-uri Affected Packages: - npm:fast-uri, affected >= 2.4.1, < 2.4.5, patched in 2.4.5 - npm:fast-uri, affected >= 3.1.2, < 3.1.6, patched in 3.1.6 - npm:fast-uri, affected >= 4.0.0, < 4.1.3, patched in 4.1.3 CWEs: - CWE-174: Double Decoding of the Same Data - CWE-918: Server-Side Request Forgery (SSRF) CVSS: - Primary: score 7.5, CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - CVSS_V3: score 7.5, CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N References: - https://github.com/fastify/fast-uri/security/advisories/GHSA-fph4-wmhf-6fwf - https://nvd.nist.gov/vuln/detail/CVE-2026-75899 - https://github.com/fastify/fast-uri/commit/2642290672e7211c990aaed3749c2ce667d0af4f - https://github.com/fastify/fast-uri/commit/8c15dbe94ec50bb8e595791ebb42c35cef0fd304 - https://github.com/fastify/fast-uri/commit/ae92a4c5d8c4b6c9e447f048d5fcbde7eebd5514 - https://cna.openjsf.org/security-advisories.html - https://github.com/fastify/fast-uri/releases/tag/v2.4.5 - https://github.com/fastify/fast-uri/releases/tag/v3.1.6 - https://github.com/fastify/fast-uri/releases/tag/v4.1.3 - https://github.com/advisories/GHSA-fph4-wmhf-6fwf